net/ipv4/inet_hashtables.c - arm/linux - Git at Google

 /*
  * INET		An implementation of the TCP/IP protocol suite for the LINUX
  *		operating system.  INET is implemented using the BSD Socket
  *		interface as the means of communication with the user level.
  *
  *		Generic INET transport hashtables
  *
  * Authors:	Lotsa people, from code originally in tcp
  *
  *	This program is free software; you can redistribute it and/or
  *      modify it under the terms of the GNU General Public License
  *      as published by the Free Software Foundation; either version
  *      2 of the License, or (at your option) any later version.
  */

 #include <linux/module.h>
 #include <linux/random.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/wait.h>
 #include <linux/vmalloc.h>

 #include <net/addrconf.h>
 #include <net/inet_connection_sock.h>
 #include <net/inet_hashtables.h>
 #include <net/secure_seq.h>
 #include <net/ip.h>
 #include <net/tcp.h>
 #include <net/sock_reuseport.h>

 static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
 			const __u16 lport, const __be32 faddr,
 			const __be16 fport)
 {
 	static u32 inet_ehash_secret __read_mostly;

 	net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret));

 	return __inet_ehashfn(laddr, lport, faddr, fport,
 			      inet_ehash_secret + net_hash_mix(net));
 }

 /* This function handles inet_sock, but also timewait and request sockets
  * for IPv4/IPv6.
  */
 static u32 sk_ehashfn(const struct sock *sk)
 {
 #if IS_ENABLED(CONFIG_IPV6)
 	if (sk->sk_family == AF_INET6 &&
 	    !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
 		return inet6_ehashfn(sock_net(sk),
 				     &sk->sk_v6_rcv_saddr, sk->sk_num,
 				     &sk->sk_v6_daddr, sk->sk_dport);
 #endif
 	return inet_ehashfn(sock_net(sk),
 			    sk->sk_rcv_saddr, sk->sk_num,
 			    sk->sk_daddr, sk->sk_dport);
 }

 /*
  * Allocate and initialize a new local port bind bucket.
  * The bindhash mutex for snum's hash chain must be held here.
  */
 struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
 						 struct net *net,
 						 struct inet_bind_hashbucket *head,
 						 const unsigned short snum)
 {
 	struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);

 	if (tb) {
 		write_pnet(&tb->ib_net, net);
 		tb->port      = snum;
 		tb->fastreuse = 0;
 		tb->fastreuseport = 0;
 		INIT_HLIST_HEAD(&tb->owners);
 		hlist_add_head(&tb->node, &head->chain);
 	}
 	return tb;
 }

 /*
  * Caller must hold hashbucket lock for this tb with local BH disabled
  */
 void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
 {
 	if (hlist_empty(&tb->owners)) {
 		__hlist_del(&tb->node);
 		kmem_cache_free(cachep, tb);
 	}
 }

 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
 		    const unsigned short snum)
 {
 	inet_sk(sk)->inet_num = snum;
 	sk_add_bind_node(sk, &tb->owners);
 	inet_csk(sk)->icsk_bind_hash = tb;
 }

 /*
  * Get rid of any references to a local port held by the given sock.
  */
 static void __inet_put_port(struct sock *sk)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 	const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
 			hashinfo->bhash_size);
 	struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
 	struct inet_bind_bucket *tb;

 	spin_lock(&head->lock);
 	tb = inet_csk(sk)->icsk_bind_hash;
 	__sk_del_bind_node(sk);
 	inet_csk(sk)->icsk_bind_hash = NULL;
 	inet_sk(sk)->inet_num = 0;
 	inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
 	spin_unlock(&head->lock);
 }

 void inet_put_port(struct sock *sk)
 {
 	local_bh_disable();
 	__inet_put_port(sk);
 	local_bh_enable();
 }
 EXPORT_SYMBOL(inet_put_port);

 int __inet_inherit_port(const struct sock *sk, struct sock *child)
 {
 	struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
 	unsigned short port = inet_sk(child)->inet_num;
 	const int bhash = inet_bhashfn(sock_net(sk), port,
 			table->bhash_size);
 	struct inet_bind_hashbucket *head = &table->bhash[bhash];
 	struct inet_bind_bucket *tb;

 	spin_lock(&head->lock);
 	tb = inet_csk(sk)->icsk_bind_hash;
 	if (unlikely(!tb)) {
 		spin_unlock(&head->lock);
 		return -ENOENT;
 	}
 	if (tb->port != port) {
 		/* NOTE: using tproxy and redirecting skbs to a proxy
 		 * on a different listener port breaks the assumption
 		 * that the listener socket's icsk_bind_hash is the same
 		 * as that of the child socket. We have to look up or
 		 * create a new bind bucket for the child here. */
 		inet_bind_bucket_for_each(tb, &head->chain) {
 			if (net_eq(ib_net(tb), sock_net(sk)) &&
 			    tb->port == port)
 				break;
 		}
 		if (!tb) {
 			tb = inet_bind_bucket_create(table->bind_bucket_cachep,
 						     sock_net(sk), head, port);
 			if (!tb) {
 				spin_unlock(&head->lock);
 				return -ENOMEM;
 			}
 		}
 	}
 	inet_bind_hash(child, tb, port);
 	spin_unlock(&head->lock);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(__inet_inherit_port);

 static inline int compute_score(struct sock *sk, struct net *net,
 				const unsigned short hnum, const __be32 daddr,
 				const int dif, const int sdif, bool exact_dif)
 {
 	int score = -1;
 	struct inet_sock *inet = inet_sk(sk);

 	if (net_eq(sock_net(sk), net) && inet->inet_num == hnum &&
 			!ipv6_only_sock(sk)) {
 		__be32 rcv_saddr = inet->inet_rcv_saddr;
 		score = sk->sk_family == PF_INET ? 2 : 1;
 		if (rcv_saddr) {
 			if (rcv_saddr != daddr)
 				return -1;
 			score += 4;
 		}
 		if (sk->sk_bound_dev_if || exact_dif) {
 			bool dev_match = (sk->sk_bound_dev_if == dif ||
 					  sk->sk_bound_dev_if == sdif);

 			if (exact_dif && !dev_match)
 				return -1;
 			if (sk->sk_bound_dev_if && dev_match)
 				score += 4;
 		}
 		if (sk->sk_incoming_cpu == raw_smp_processor_id())
 			score++;
 	}
 	return score;
 }

 /*
  * Here are some nice properties to exploit here. The BSD API
  * does not allow a listening sock to specify the remote port nor the
  * remote address for the connection. So always assume those are both
  * wildcarded during the search since they can never be otherwise.
  */

 /* called with rcu_read_lock() : No refcount taken on the socket */
 struct sock *__inet_lookup_listener(struct net *net,
 				    struct inet_hashinfo *hashinfo,
 				    struct sk_buff *skb, int doff,
 				    const __be32 saddr, __be16 sport,
 				    const __be32 daddr, const unsigned short hnum,
 				    const int dif, const int sdif)
 {
 	unsigned int hash = inet_lhashfn(net, hnum);
 	struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
 	int score, hiscore = 0, matches = 0, reuseport = 0;
 	bool exact_dif = inet_exact_dif_match(net, skb);
 	struct sock *sk, *result = NULL;
 	u32 phash = 0;

 	sk_for_each_rcu(sk, &ilb->head) {
 		score = compute_score(sk, net, hnum, daddr,
 				      dif, sdif, exact_dif);
 		if (score > hiscore) {
 			reuseport = sk->sk_reuseport;
 			if (reuseport) {
 				phash = inet_ehashfn(net, daddr, hnum,
 						     saddr, sport);
 				result = reuseport_select_sock(sk, phash,
 							       skb, doff);
 				if (result)
 					return result;
 				matches = 1;
 			}
 			result = sk;
 			hiscore = score;
 		} else if (score == hiscore && reuseport) {
 			matches++;
 			if (reciprocal_scale(phash, matches) == 0)
 				result = sk;
 			phash = next_pseudo_random32(phash);
 		}
 	}
 	return result;
 }
 EXPORT_SYMBOL_GPL(__inet_lookup_listener);

 /* All sockets share common refcount, but have different destructors */
 void sock_gen_put(struct sock *sk)
 {
 	if (!refcount_dec_and_test(&sk->sk_refcnt))
 		return;

 	if (sk->sk_state == TCP_TIME_WAIT)
 		inet_twsk_free(inet_twsk(sk));
 	else if (sk->sk_state == TCP_NEW_SYN_RECV)
 		reqsk_free(inet_reqsk(sk));
 	else
 		sk_free(sk);
 }
 EXPORT_SYMBOL_GPL(sock_gen_put);

 void sock_edemux(struct sk_buff *skb)
 {
 	sock_gen_put(skb->sk);
 }
 EXPORT_SYMBOL(sock_edemux);

 struct sock *__inet_lookup_established(struct net *net,
 				  struct inet_hashinfo *hashinfo,
 				  const __be32 saddr, const __be16 sport,
 				  const __be32 daddr, const u16 hnum,
 				  const int dif, const int sdif)
 {
 	INET_ADDR_COOKIE(acookie, saddr, daddr);
 	const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
 	struct sock *sk;
 	const struct hlist_nulls_node *node;
 	/* Optimize here for direct hit, only listening connections can
 	 * have wildcards anyways.
 	 */
 	unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
 	unsigned int slot = hash & hashinfo->ehash_mask;
 	struct inet_ehash_bucket *head = &hashinfo->ehash[slot];

 begin:
 	sk_nulls_for_each_rcu(sk, node, &head->chain) {
 		if (sk->sk_hash != hash)
 			continue;
 		if (likely(INET_MATCH(sk, net, acookie,
 				      saddr, daddr, ports, dif, sdif))) {
 			if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
 				goto out;
 			if (unlikely(!INET_MATCH(sk, net, acookie,
 						 saddr, daddr, ports,
 						 dif, sdif))) {
 				sock_gen_put(sk);
 				goto begin;
 			}
 			goto found;
 		}
 	}
 	/*
 	 * if the nulls value we got at the end of this lookup is
 	 * not the expected one, we must restart lookup.
 	 * We probably met an item that was moved to another chain.
 	 */
 	if (get_nulls_value(node) != slot)
 		goto begin;
 out:
 	sk = NULL;
 found:
 	return sk;
 }
 EXPORT_SYMBOL_GPL(__inet_lookup_established);

 /* called with local bh disabled */
 static int __inet_check_established(struct inet_timewait_death_row *death_row,
 				    struct sock *sk, __u16 lport,
 				    struct inet_timewait_sock **twp)
 {
 	struct inet_hashinfo *hinfo = death_row->hashinfo;
 	struct inet_sock *inet = inet_sk(sk);
 	__be32 daddr = inet->inet_rcv_saddr;
 	__be32 saddr = inet->inet_daddr;
 	int dif = sk->sk_bound_dev_if;
 	struct net *net = sock_net(sk);
 	int sdif = l3mdev_master_ifindex_by_index(net, dif);
 	INET_ADDR_COOKIE(acookie, saddr, daddr);
 	const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
 	unsigned int hash = inet_ehashfn(net, daddr, lport,
 					 saddr, inet->inet_dport);
 	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
 	spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
 	struct sock *sk2;
 	const struct hlist_nulls_node *node;
 	struct inet_timewait_sock *tw = NULL;

 	spin_lock(lock);

 	sk_nulls_for_each(sk2, node, &head->chain) {
 		if (sk2->sk_hash != hash)
 			continue;

 		if (likely(INET_MATCH(sk2, net, acookie,
 					 saddr, daddr, ports, dif, sdif))) {
 			if (sk2->sk_state == TCP_TIME_WAIT) {
 				tw = inet_twsk(sk2);
 				if (twsk_unique(sk, sk2, twp))
 					break;
 			}
 			goto not_unique;
 		}
 	}

 	/* Must record num and sport now. Otherwise we will see
 	 * in hash table socket with a funny identity.
 	 */
 	inet->inet_num = lport;
 	inet->inet_sport = htons(lport);
 	sk->sk_hash = hash;
 	WARN_ON(!sk_unhashed(sk));
 	__sk_nulls_add_node_rcu(sk, &head->chain);
 	if (tw) {
 		sk_nulls_del_node_init_rcu((struct sock *)tw);
 		__NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED);
 	}
 	spin_unlock(lock);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);

 	if (twp) {
 		*twp = tw;
 	} else if (tw) {
 		/* Silly. Should hash-dance instead... */
 		inet_twsk_deschedule_put(tw);
 	}
 	return 0;

 not_unique:
 	spin_unlock(lock);
 	return -EADDRNOTAVAIL;
 }

 static u32 inet_sk_port_offset(const struct sock *sk)
 {
 	const struct inet_sock *inet = inet_sk(sk);

 	return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
 					  inet->inet_daddr,
 					  inet->inet_dport);
 }

 /* insert a socket into ehash, and eventually remove another one
  * (The another one can be a SYN_RECV or TIMEWAIT
  */
 bool inet_ehash_insert(struct sock *sk, struct sock *osk)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 	struct hlist_nulls_head *list;
 	struct inet_ehash_bucket *head;
 	spinlock_t *lock;
 	bool ret = true;

 	WARN_ON_ONCE(!sk_unhashed(sk));

 	sk->sk_hash = sk_ehashfn(sk);
 	head = inet_ehash_bucket(hashinfo, sk->sk_hash);
 	list = &head->chain;
 	lock = inet_ehash_lockp(hashinfo, sk->sk_hash);

 	spin_lock(lock);
 	if (osk) {
 		WARN_ON_ONCE(sk->sk_hash != osk->sk_hash);
 		ret = sk_nulls_del_node_init_rcu(osk);
 	}
 	if (ret)
 		__sk_nulls_add_node_rcu(sk, list);
 	spin_unlock(lock);
 	return ret;
 }

 bool inet_ehash_nolisten(struct sock *sk, struct sock *osk)
 {
 	bool ok = inet_ehash_insert(sk, osk);

 	if (ok) {
 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 	} else {
 		percpu_counter_inc(sk->sk_prot->orphan_count);
 		sk->sk_state = TCP_CLOSE;
 		sock_set_flag(sk, SOCK_DEAD);
 		inet_csk_destroy_sock(sk);
 	}
 	return ok;
 }
 EXPORT_SYMBOL_GPL(inet_ehash_nolisten);

 static int inet_reuseport_add_sock(struct sock *sk,
 				   struct inet_listen_hashbucket *ilb)
 {
 	struct inet_bind_bucket *tb = inet_csk(sk)->icsk_bind_hash;
 	struct sock *sk2;
 	kuid_t uid = sock_i_uid(sk);

 	sk_for_each_rcu(sk2, &ilb->head) {
 		if (sk2 != sk &&
 		    sk2->sk_family == sk->sk_family &&
 		    ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
 		    sk2->sk_bound_dev_if == sk->sk_bound_dev_if &&
 		    inet_csk(sk2)->icsk_bind_hash == tb &&
 		    sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
 		    inet_rcv_saddr_equal(sk, sk2, false))
 			return reuseport_add_sock(sk, sk2);
 	}

 	return reuseport_alloc(sk);
 }

 int __inet_hash(struct sock *sk, struct sock *osk)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 	struct inet_listen_hashbucket *ilb;
 	int err = 0;

 	if (sk->sk_state != TCP_LISTEN) {
 		inet_ehash_nolisten(sk, osk);
 		return 0;
 	}
 	WARN_ON(!sk_unhashed(sk));
 	ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];

 	spin_lock(&ilb->lock);
 	if (sk->sk_reuseport) {
 		err = inet_reuseport_add_sock(sk, ilb);
 		if (err)
 			goto unlock;
 	}
 	if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
 		sk->sk_family == AF_INET6)
 		hlist_add_tail_rcu(&sk->sk_node, &ilb->head);
 	else
 		hlist_add_head_rcu(&sk->sk_node, &ilb->head);
 	sock_set_flag(sk, SOCK_RCU_FREE);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 unlock:
 	spin_unlock(&ilb->lock);

 	return err;
 }
 EXPORT_SYMBOL(__inet_hash);

 int inet_hash(struct sock *sk)
 {
 	int err = 0;

 	if (sk->sk_state != TCP_CLOSE) {
 		local_bh_disable();
 		err = __inet_hash(sk, NULL);
 		local_bh_enable();
 	}

 	return err;
 }
 EXPORT_SYMBOL_GPL(inet_hash);

 void inet_unhash(struct sock *sk)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 	spinlock_t *lock;
 	bool listener = false;
 	int done;

 	if (sk_unhashed(sk))
 		return;

 	if (sk->sk_state == TCP_LISTEN) {
 		lock = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)].lock;
 		listener = true;
 	} else {
 		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 	}
 	spin_lock_bh(lock);
 	if (rcu_access_pointer(sk->sk_reuseport_cb))
 		reuseport_detach_sock(sk);
 	if (listener)
 		done = __sk_del_node_init(sk);
 	else
 		done = __sk_nulls_del_node_init_rcu(sk);
 	if (done)
 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 	spin_unlock_bh(lock);
 }
 EXPORT_SYMBOL_GPL(inet_unhash);

 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 		struct sock *sk, u32 port_offset,
 		int (*check_established)(struct inet_timewait_death_row *,
 			struct sock *, __u16, struct inet_timewait_sock **))
 {
 	struct inet_hashinfo *hinfo = death_row->hashinfo;
 	struct inet_timewait_sock *tw = NULL;
 	struct inet_bind_hashbucket *head;
 	int port = inet_sk(sk)->inet_num;
 	struct net *net = sock_net(sk);
 	struct inet_bind_bucket *tb;
 	u32 remaining, offset;
 	int ret, i, low, high;
 	static u32 hint;

 	if (port) {
 		head = &hinfo->bhash[inet_bhashfn(net, port,
 						  hinfo->bhash_size)];
 		tb = inet_csk(sk)->icsk_bind_hash;
 		spin_lock_bh(&head->lock);
 		if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
 			inet_ehash_nolisten(sk, NULL);
 			spin_unlock_bh(&head->lock);
 			return 0;
 		}
 		spin_unlock(&head->lock);
 		/* No definite answer... Walk to established hash table */
 		ret = check_established(death_row, sk, port, NULL);
 		local_bh_enable();
 		return ret;
 	}

 	inet_get_local_port_range(net, &low, &high);
 	high++; /* [32768, 60999] -> [32768, 61000[ */
 	remaining = high - low;
 	if (likely(remaining > 1))
 		remaining &= ~1U;

 	offset = (hint + port_offset) % remaining;
 	/* In first pass we try ports of @low parity.
 	 * inet_csk_get_port() does the opposite choice.
 	 */
 	offset &= ~1U;
 other_parity_scan:
 	port = low + offset;
 	for (i = 0; i < remaining; i += 2, port += 2) {
 		if (unlikely(port >= high))
 			port -= remaining;
 		if (inet_is_local_reserved_port(net, port))
 			continue;
 		head = &hinfo->bhash[inet_bhashfn(net, port,
 						  hinfo->bhash_size)];
 		spin_lock_bh(&head->lock);

 		/* Does not bother with rcv_saddr checks, because
 		 * the established check is already unique enough.
 		 */
 		inet_bind_bucket_for_each(tb, &head->chain) {
 			if (net_eq(ib_net(tb), net) && tb->port == port) {
 				if (tb->fastreuse >= 0 ||
 				    tb->fastreuseport >= 0)
 					goto next_port;
 				WARN_ON(hlist_empty(&tb->owners));
 				if (!check_established(death_row, sk,
 						       port, &tw))
 					goto ok;
 				goto next_port;
 			}
 		}

 		tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
 					     net, head, port);
 		if (!tb) {
 			spin_unlock_bh(&head->lock);
 			return -ENOMEM;
 		}
 		tb->fastreuse = -1;
 		tb->fastreuseport = -1;
 		goto ok;
 next_port:
 		spin_unlock_bh(&head->lock);
 		cond_resched();
 	}

 	offset++;
 	if ((offset & 1) && remaining > 1)
 		goto other_parity_scan;

 	return -EADDRNOTAVAIL;

 ok:
 	hint += i + 2;

 	/* Head lock still held and bh's disabled */
 	inet_bind_hash(sk, tb, port);
 	if (sk_unhashed(sk)) {
 		inet_sk(sk)->inet_sport = htons(port);
 		inet_ehash_nolisten(sk, (struct sock *)tw);
 	}
 	if (tw)
 		inet_twsk_bind_unhash(tw, hinfo);
 	spin_unlock(&head->lock);
 	if (tw)
 		inet_twsk_deschedule_put(tw);
 	local_bh_enable();
 	return 0;
 }

 /*
  * Bind a port for a connect operation and hash it.
  */
 int inet_hash_connect(struct inet_timewait_death_row *death_row,
 		      struct sock *sk)
 {
 	u32 port_offset = 0;

 	if (!inet_sk(sk)->inet_num)
 		port_offset = inet_sk_port_offset(sk);
 	return __inet_hash_connect(death_row, sk, port_offset,
 				   __inet_check_established);
 }
 EXPORT_SYMBOL_GPL(inet_hash_connect);

 void inet_hashinfo_init(struct inet_hashinfo *h)
 {
 	int i;

 	for (i = 0; i < INET_LHTABLE_SIZE; i++) {
 		spin_lock_init(&h->listening_hash[i].lock);
 		INIT_HLIST_HEAD(&h->listening_hash[i].head);
 	}
 }
 EXPORT_SYMBOL_GPL(inet_hashinfo_init);

 int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
 {
 	unsigned int locksz = sizeof(spinlock_t);
 	unsigned int i, nblocks = 1;

 	if (locksz != 0) {
 		/* allocate 2 cache lines or at least one spinlock per cpu */
 		nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U);
 		nblocks = roundup_pow_of_two(nblocks * num_possible_cpus());

 		/* no more locks than number of hash buckets */
 		nblocks = min(nblocks, hashinfo->ehash_mask + 1);

 		hashinfo->ehash_locks = kvmalloc_array(nblocks, locksz, GFP_KERNEL);
 		if (!hashinfo->ehash_locks)
 			return -ENOMEM;

 		for (i = 0; i < nblocks; i++)
 			spin_lock_init(&hashinfo->ehash_locks[i]);
 	}
 	hashinfo->ehash_locks_mask = nblocks - 1;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc);
	/*
	* INET An implementation of the TCP/IP protocol suite for the LINUX
	* operating system. INET is implemented using the BSD Socket
	* interface as the means of communication with the user level.
	*
	* Generic INET transport hashtables
	*
	* Authors: Lotsa people, from code originally in tcp
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*/

	#include <linux/module.h>
	#include <linux/random.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/wait.h>
	#include <linux/vmalloc.h>

	#include <net/addrconf.h>
	#include <net/inet_connection_sock.h>
	#include <net/inet_hashtables.h>
	#include <net/secure_seq.h>
	#include <net/ip.h>
	#include <net/tcp.h>
	#include <net/sock_reuseport.h>

	static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
	const __u16 lport, const __be32 faddr,
	const __be16 fport)
	{
	static u32 inet_ehash_secret __read_mostly;

	net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret));

	return __inet_ehashfn(laddr, lport, faddr, fport,
	inet_ehash_secret + net_hash_mix(net));
	}

	/* This function handles inet_sock, but also timewait and request sockets
	* for IPv4/IPv6.
	*/
	static u32 sk_ehashfn(const struct sock *sk)
	{
	#if IS_ENABLED(CONFIG_IPV6)
	if (sk->sk_family == AF_INET6 &&
	!ipv6_addr_v4mapped(&sk->sk_v6_daddr))
	return inet6_ehashfn(sock_net(sk),
	&sk->sk_v6_rcv_saddr, sk->sk_num,
	&sk->sk_v6_daddr, sk->sk_dport);
	#endif
	return inet_ehashfn(sock_net(sk),
	sk->sk_rcv_saddr, sk->sk_num,
	sk->sk_daddr, sk->sk_dport);
	}

	/*
	* Allocate and initialize a new local port bind bucket.
	* The bindhash mutex for snum's hash chain must be held here.
	*/
	struct inet_bind_bucket inet_bind_bucket_create(struct kmem_cache cachep,
	struct net *net,
	struct inet_bind_hashbucket *head,
	const unsigned short snum)
	{
	struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);

	if (tb) {
	write_pnet(&tb->ib_net, net);
	tb->port = snum;
	tb->fastreuse = 0;
	tb->fastreuseport = 0;
	INIT_HLIST_HEAD(&tb->owners);
	hlist_add_head(&tb->node, &head->chain);
	}
	return tb;
	}

	/*
	* Caller must hold hashbucket lock for this tb with local BH disabled
	*/
	void inet_bind_bucket_destroy(struct kmem_cache cachep, struct inet_bind_bucket tb)
	{
	if (hlist_empty(&tb->owners)) {
	__hlist_del(&tb->node);
	kmem_cache_free(cachep, tb);
	}
	}

	void inet_bind_hash(struct sock sk, struct inet_bind_bucket tb,
	const unsigned short snum)
	{
	inet_sk(sk)->inet_num = snum;
	sk_add_bind_node(sk, &tb->owners);
	inet_csk(sk)->icsk_bind_hash = tb;
	}

	/*
	* Get rid of any references to a local port held by the given sock.
	*/
	static void __inet_put_port(struct sock *sk)
	{
	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
	const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
	hashinfo->bhash_size);
	struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
	struct inet_bind_bucket *tb;

	spin_lock(&head->lock);
	tb = inet_csk(sk)->icsk_bind_hash;
	__sk_del_bind_node(sk);
	inet_csk(sk)->icsk_bind_hash = NULL;
	inet_sk(sk)->inet_num = 0;
	inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
	spin_unlock(&head->lock);
	}

	void inet_put_port(struct sock *sk)
	{
	local_bh_disable();
	__inet_put_port(sk);
	local_bh_enable();
	}
	EXPORT_SYMBOL(inet_put_port);

	int __inet_inherit_port(const struct sock sk, struct sock child)
	{
	struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
	unsigned short port = inet_sk(child)->inet_num;
	const int bhash = inet_bhashfn(sock_net(sk), port,
	table->bhash_size);
	struct inet_bind_hashbucket *head = &table->bhash[bhash];
	struct inet_bind_bucket *tb;

	spin_lock(&head->lock);
	tb = inet_csk(sk)->icsk_bind_hash;
	if (unlikely(!tb)) {
	spin_unlock(&head->lock);
	return -ENOENT;
	}
	if (tb->port != port) {
	/* NOTE: using tproxy and redirecting skbs to a proxy
	* on a different listener port breaks the assumption
	* that the listener socket's icsk_bind_hash is the same
	* as that of the child socket. We have to look up or
	* create a new bind bucket for the child here. */
	inet_bind_bucket_for_each(tb, &head->chain) {
	if (net_eq(ib_net(tb), sock_net(sk)) &&
	tb->port == port)
	break;
	}
	if (!tb) {
	tb = inet_bind_bucket_create(table->bind_bucket_cachep,
	sock_net(sk), head, port);
	if (!tb) {
	spin_unlock(&head->lock);
	return -ENOMEM;
	}
	}
	}
	inet_bind_hash(child, tb, port);
	spin_unlock(&head->lock);

	return 0;
	}
	EXPORT_SYMBOL_GPL(__inet_inherit_port);

	static inline int compute_score(struct sock sk, struct net net,
	const unsigned short hnum, const __be32 daddr,
	const int dif, const int sdif, bool exact_dif)
	{
	int score = -1;
	struct inet_sock *inet = inet_sk(sk);

	if (net_eq(sock_net(sk), net) && inet->inet_num == hnum &&
	!ipv6_only_sock(sk)) {
	__be32 rcv_saddr = inet->inet_rcv_saddr;
	score = sk->sk_family == PF_INET ? 2 : 1;
	if (rcv_saddr) {
	if (rcv_saddr != daddr)
	return -1;
	score += 4;
	}
	if (sk->sk_bound_dev_if \|\| exact_dif) {
	bool dev_match = (sk->sk_bound_dev_if == dif \|\|
	sk->sk_bound_dev_if == sdif);

	if (exact_dif && !dev_match)
	return -1;
	if (sk->sk_bound_dev_if && dev_match)
	score += 4;
	}
	if (sk->sk_incoming_cpu == raw_smp_processor_id())
	score++;
	}
	return score;
	}

	/*
	* Here are some nice properties to exploit here. The BSD API
	* does not allow a listening sock to specify the remote port nor the
	* remote address for the connection. So always assume those are both
	* wildcarded during the search since they can never be otherwise.
	*/

	/* called with rcu_read_lock() : No refcount taken on the socket */
	struct sock __inet_lookup_listener(struct net net,
	struct inet_hashinfo *hashinfo,
	struct sk_buff *skb, int doff,
	const __be32 saddr, __be16 sport,
	const __be32 daddr, const unsigned short hnum,
	const int dif, const int sdif)
	{
	unsigned int hash = inet_lhashfn(net, hnum);
	struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
	int score, hiscore = 0, matches = 0, reuseport = 0;
	bool exact_dif = inet_exact_dif_match(net, skb);
	struct sock sk, result = NULL;
	u32 phash = 0;

	sk_for_each_rcu(sk, &ilb->head) {
	score = compute_score(sk, net, hnum, daddr,
	dif, sdif, exact_dif);
	if (score > hiscore) {
	reuseport = sk->sk_reuseport;
	if (reuseport) {
	phash = inet_ehashfn(net, daddr, hnum,
	saddr, sport);
	result = reuseport_select_sock(sk, phash,
	skb, doff);
	if (result)
	return result;
	matches = 1;
	}
	result = sk;
	hiscore = score;
	} else if (score == hiscore && reuseport) {
	matches++;
	if (reciprocal_scale(phash, matches) == 0)
	result = sk;
	phash = next_pseudo_random32(phash);
	}
	}
	return result;
	}
	EXPORT_SYMBOL_GPL(__inet_lookup_listener);

	/* All sockets share common refcount, but have different destructors */
	void sock_gen_put(struct sock *sk)
	{
	if (!refcount_dec_and_test(&sk->sk_refcnt))
	return;

	if (sk->sk_state == TCP_TIME_WAIT)
	inet_twsk_free(inet_twsk(sk));
	else if (sk->sk_state == TCP_NEW_SYN_RECV)
	reqsk_free(inet_reqsk(sk));
	else
	sk_free(sk);
	}
	EXPORT_SYMBOL_GPL(sock_gen_put);

	void sock_edemux(struct sk_buff *skb)
	{
	sock_gen_put(skb->sk);
	}
	EXPORT_SYMBOL(sock_edemux);

	struct sock __inet_lookup_established(struct net net,
	struct inet_hashinfo *hashinfo,
	const __be32 saddr, const __be16 sport,
	const __be32 daddr, const u16 hnum,
	const int dif, const int sdif)
	{
	INET_ADDR_COOKIE(acookie, saddr, daddr);
	const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
	struct sock *sk;
	const struct hlist_nulls_node *node;
	/* Optimize here for direct hit, only listening connections can
	* have wildcards anyways.
	*/
	unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
	unsigned int slot = hash & hashinfo->ehash_mask;
	struct inet_ehash_bucket *head = &hashinfo->ehash[slot];

	begin:
	sk_nulls_for_each_rcu(sk, node, &head->chain) {
	if (sk->sk_hash != hash)
	continue;
	if (likely(INET_MATCH(sk, net, acookie,
	saddr, daddr, ports, dif, sdif))) {
	if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
	goto out;
	if (unlikely(!INET_MATCH(sk, net, acookie,
	saddr, daddr, ports,
	dif, sdif))) {
	sock_gen_put(sk);
	goto begin;
	}
	goto found;
	}
	}
	/*
	* if the nulls value we got at the end of this lookup is
	* not the expected one, we must restart lookup.
	* We probably met an item that was moved to another chain.
	*/
	if (get_nulls_value(node) != slot)
	goto begin;
	out:
	sk = NULL;
	found:
	return sk;
	}
	EXPORT_SYMBOL_GPL(__inet_lookup_established);

	/* called with local bh disabled */
	static int __inet_check_established(struct inet_timewait_death_row *death_row,
	struct sock *sk, __u16 lport,
	struct inet_timewait_sock **twp)
	{
	struct inet_hashinfo *hinfo = death_row->hashinfo;
	struct inet_sock *inet = inet_sk(sk);
	__be32 daddr = inet->inet_rcv_saddr;
	__be32 saddr = inet->inet_daddr;
	int dif = sk->sk_bound_dev_if;
	struct net *net = sock_net(sk);
	int sdif = l3mdev_master_ifindex_by_index(net, dif);
	INET_ADDR_COOKIE(acookie, saddr, daddr);
	const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
	unsigned int hash = inet_ehashfn(net, daddr, lport,
	saddr, inet->inet_dport);
	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
	spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
	struct sock *sk2;
	const struct hlist_nulls_node *node;
	struct inet_timewait_sock *tw = NULL;

	spin_lock(lock);

	sk_nulls_for_each(sk2, node, &head->chain) {
	if (sk2->sk_hash != hash)
	continue;

	if (likely(INET_MATCH(sk2, net, acookie,
	saddr, daddr, ports, dif, sdif))) {
	if (sk2->sk_state == TCP_TIME_WAIT) {
	tw = inet_twsk(sk2);
	if (twsk_unique(sk, sk2, twp))
	break;
	}
	goto not_unique;
	}
	}

	/* Must record num and sport now. Otherwise we will see
	* in hash table socket with a funny identity.
	*/
	inet->inet_num = lport;
	inet->inet_sport = htons(lport);
	sk->sk_hash = hash;
	WARN_ON(!sk_unhashed(sk));
	__sk_nulls_add_node_rcu(sk, &head->chain);
	if (tw) {
	sk_nulls_del_node_init_rcu((struct sock *)tw);
	__NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED);
	}
	spin_unlock(lock);
	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);

	if (twp) {
	*twp = tw;
	} else if (tw) {
	/* Silly. Should hash-dance instead... */
	inet_twsk_deschedule_put(tw);
	}
	return 0;

	not_unique:
	spin_unlock(lock);
	return -EADDRNOTAVAIL;
	}

	static u32 inet_sk_port_offset(const struct sock *sk)
	{
	const struct inet_sock *inet = inet_sk(sk);

	return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
	inet->inet_daddr,
	inet->inet_dport);
	}

	/* insert a socket into ehash, and eventually remove another one
	* (The another one can be a SYN_RECV or TIMEWAIT
	*/
	bool inet_ehash_insert(struct sock sk, struct sock osk)
	{
	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
	struct hlist_nulls_head *list;
	struct inet_ehash_bucket *head;
	spinlock_t *lock;
	bool ret = true;

	WARN_ON_ONCE(!sk_unhashed(sk));

	sk->sk_hash = sk_ehashfn(sk);
	head = inet_ehash_bucket(hashinfo, sk->sk_hash);
	list = &head->chain;
	lock = inet_ehash_lockp(hashinfo, sk->sk_hash);

	spin_lock(lock);
	if (osk) {
	WARN_ON_ONCE(sk->sk_hash != osk->sk_hash);
	ret = sk_nulls_del_node_init_rcu(osk);
	}
	if (ret)
	__sk_nulls_add_node_rcu(sk, list);
	spin_unlock(lock);
	return ret;
	}

	bool inet_ehash_nolisten(struct sock sk, struct sock osk)
	{
	bool ok = inet_ehash_insert(sk, osk);

	if (ok) {
	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
	} else {
	percpu_counter_inc(sk->sk_prot->orphan_count);
	sk->sk_state = TCP_CLOSE;
	sock_set_flag(sk, SOCK_DEAD);
	inet_csk_destroy_sock(sk);
	}
	return ok;
	}
	EXPORT_SYMBOL_GPL(inet_ehash_nolisten);

	static int inet_reuseport_add_sock(struct sock *sk,
	struct inet_listen_hashbucket *ilb)
	{
	struct inet_bind_bucket *tb = inet_csk(sk)->icsk_bind_hash;
	struct sock *sk2;
	kuid_t uid = sock_i_uid(sk);

	sk_for_each_rcu(sk2, &ilb->head) {
	if (sk2 != sk &&
	sk2->sk_family == sk->sk_family &&
	ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
	sk2->sk_bound_dev_if == sk->sk_bound_dev_if &&
	inet_csk(sk2)->icsk_bind_hash == tb &&
	sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
	inet_rcv_saddr_equal(sk, sk2, false))
	return reuseport_add_sock(sk, sk2);
	}

	return reuseport_alloc(sk);
	}

	int __inet_hash(struct sock sk, struct sock osk)
	{
	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
	struct inet_listen_hashbucket *ilb;
	int err = 0;

	if (sk->sk_state != TCP_LISTEN) {
	inet_ehash_nolisten(sk, osk);
	return 0;
	}
	WARN_ON(!sk_unhashed(sk));
	ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];

	spin_lock(&ilb->lock);
	if (sk->sk_reuseport) {
	err = inet_reuseport_add_sock(sk, ilb);
	if (err)
	goto unlock;
	}
	if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
	sk->sk_family == AF_INET6)
	hlist_add_tail_rcu(&sk->sk_node, &ilb->head);
	else
	hlist_add_head_rcu(&sk->sk_node, &ilb->head);
	sock_set_flag(sk, SOCK_RCU_FREE);
	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
	unlock:
	spin_unlock(&ilb->lock);

	return err;
	}
	EXPORT_SYMBOL(__inet_hash);

	int inet_hash(struct sock *sk)
	{
	int err = 0;

	if (sk->sk_state != TCP_CLOSE) {
	local_bh_disable();
	err = __inet_hash(sk, NULL);
	local_bh_enable();
	}

	return err;
	}
	EXPORT_SYMBOL_GPL(inet_hash);

	void inet_unhash(struct sock *sk)
	{
	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
	spinlock_t *lock;
	bool listener = false;
	int done;

	if (sk_unhashed(sk))
	return;

	if (sk->sk_state == TCP_LISTEN) {
	lock = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)].lock;
	listener = true;
	} else {
	lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
	}
	spin_lock_bh(lock);
	if (rcu_access_pointer(sk->sk_reuseport_cb))
	reuseport_detach_sock(sk);
	if (listener)
	done = __sk_del_node_init(sk);
	else
	done = __sk_nulls_del_node_init_rcu(sk);
	if (done)
	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
	spin_unlock_bh(lock);
	}
	EXPORT_SYMBOL_GPL(inet_unhash);

	int __inet_hash_connect(struct inet_timewait_death_row *death_row,
	struct sock *sk, u32 port_offset,
	int (check_established)(struct inet_timewait_death_row ,
	struct sock , __u16, struct inet_timewait_sock *))
	{
	struct inet_hashinfo *hinfo = death_row->hashinfo;
	struct inet_timewait_sock *tw = NULL;
	struct inet_bind_hashbucket *head;
	int port = inet_sk(sk)->inet_num;
	struct net *net = sock_net(sk);
	struct inet_bind_bucket *tb;
	u32 remaining, offset;
	int ret, i, low, high;
	static u32 hint;

	if (port) {
	head = &hinfo->bhash[inet_bhashfn(net, port,
	hinfo->bhash_size)];
	tb = inet_csk(sk)->icsk_bind_hash;
	spin_lock_bh(&head->lock);
	if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
	inet_ehash_nolisten(sk, NULL);
	spin_unlock_bh(&head->lock);
	return 0;
	}
	spin_unlock(&head->lock);
	/* No definite answer... Walk to established hash table */
	ret = check_established(death_row, sk, port, NULL);
	local_bh_enable();
	return ret;
	}

	inet_get_local_port_range(net, &low, &high);
	high++; /* [32768, 60999] -> [32768, 61000[ */
	remaining = high - low;
	if (likely(remaining > 1))
	remaining &= ~1U;

	offset = (hint + port_offset) % remaining;
	/* In first pass we try ports of @low parity.
	* inet_csk_get_port() does the opposite choice.
	*/
	offset &= ~1U;
	other_parity_scan:
	port = low + offset;
	for (i = 0; i < remaining; i += 2, port += 2) {
	if (unlikely(port >= high))
	port -= remaining;
	if (inet_is_local_reserved_port(net, port))
	continue;
	head = &hinfo->bhash[inet_bhashfn(net, port,
	hinfo->bhash_size)];
	spin_lock_bh(&head->lock);

	/* Does not bother with rcv_saddr checks, because
	* the established check is already unique enough.
	*/
	inet_bind_bucket_for_each(tb, &head->chain) {
	if (net_eq(ib_net(tb), net) && tb->port == port) {
	if (tb->fastreuse >= 0 \|\|
	tb->fastreuseport >= 0)
	goto next_port;
	WARN_ON(hlist_empty(&tb->owners));
	if (!check_established(death_row, sk,
	port, &tw))
	goto ok;
	goto next_port;
	}
	}

	tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
	net, head, port);
	if (!tb) {
	spin_unlock_bh(&head->lock);
	return -ENOMEM;
	}
	tb->fastreuse = -1;
	tb->fastreuseport = -1;
	goto ok;
	next_port:
	spin_unlock_bh(&head->lock);
	cond_resched();
	}

	offset++;
	if ((offset & 1) && remaining > 1)
	goto other_parity_scan;

	return -EADDRNOTAVAIL;

	ok:
	hint += i + 2;

	/* Head lock still held and bh's disabled */
	inet_bind_hash(sk, tb, port);
	if (sk_unhashed(sk)) {
	inet_sk(sk)->inet_sport = htons(port);
	inet_ehash_nolisten(sk, (struct sock *)tw);
	}
	if (tw)
	inet_twsk_bind_unhash(tw, hinfo);
	spin_unlock(&head->lock);
	if (tw)
	inet_twsk_deschedule_put(tw);
	local_bh_enable();
	return 0;
	}

	/*
	* Bind a port for a connect operation and hash it.
	*/
	int inet_hash_connect(struct inet_timewait_death_row *death_row,
	struct sock *sk)
	{
	u32 port_offset = 0;

	if (!inet_sk(sk)->inet_num)
	port_offset = inet_sk_port_offset(sk);
	return __inet_hash_connect(death_row, sk, port_offset,
	__inet_check_established);
	}
	EXPORT_SYMBOL_GPL(inet_hash_connect);

	void inet_hashinfo_init(struct inet_hashinfo *h)
	{
	int i;

	for (i = 0; i < INET_LHTABLE_SIZE; i++) {
	spin_lock_init(&h->listening_hash[i].lock);
	INIT_HLIST_HEAD(&h->listening_hash[i].head);
	}
	}
	EXPORT_SYMBOL_GPL(inet_hashinfo_init);

	int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
	{
	unsigned int locksz = sizeof(spinlock_t);
	unsigned int i, nblocks = 1;

	if (locksz != 0) {
	/* allocate 2 cache lines or at least one spinlock per cpu */
	nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U);
	nblocks = roundup_pow_of_two(nblocks * num_possible_cpus());

	/* no more locks than number of hash buckets */
	nblocks = min(nblocks, hashinfo->ehash_mask + 1);

	hashinfo->ehash_locks = kvmalloc_array(nblocks, locksz, GFP_KERNEL);
	if (!hashinfo->ehash_locks)
	return -ENOMEM;

	for (i = 0; i < nblocks; i++)
	spin_lock_init(&hashinfo->ehash_locks[i]);
	}
	hashinfo->ehash_locks_mask = nblocks - 1;
	return 0;
	}
	EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc);